717A Low Power Issue

[workinonit]

So I'm handy enough on small engines that I rarely have to have anyone work on any of mine but this issue has stumped me. I was cutting yesterday and like the flip of a switch the power on the mower went to 3/4 or maybe even 2/3 of what it normally runs. And not just RPMs but power. It never sounded like one of the cylinders stopped firing and such is the case. It actually runs smoothly and one would think normal until a load is applied. I replaced the fuel filter and went to get 2 plugs and replaced them. Still the same. I haven't gone as far as seeing if the choke is partially closed but it does seem to be running rich. The linkages are in the normal position but I will check that tomorrow. I have 2 ZTs and never had this issue so I'm open for suggesstions from any of you small engine guys. BTW, I assume all of these were Kawasaki. If not it is a 19 HP.

 

[jaxs]

Since it was"like the flip of a switch" rather than intermitently and/or progressive,perhaps some kind of trash jambed the governor link. I don't reccomend adjusting or general tinkering with governers. Just close inspection in this case.

 

[Roadworthy]

When the power on my Craftsman mower would drop like that it was because one cylinder quit working. Somehow one of the valves would disconnect itself so one cylinder was doing all the work. The fix was simple. I'm now using about an ounce of Marvel Mystery Oil per gallon of gasoline on the advice of the service guy and the problem no longer happens.

 

[RandyT]

Could be anything from a bad spark plug, ignition module that has failed. Push rod came loose and dropped out of position. About the only time fuel comes into play when loosing one cylinder is with two barrel carbs.

With the engine running remove or ground out one plug wire at a time. If it keeps running with one then reconnect an remove the other one. If it dies the problem is with the opposite cylinder.

 

[workinonit]

Thanks guys. I'm about to head out there and I'll pull the plug wires. I was actually planning on doing this. I assumed both cylinders were firing because it does seem to run just fine, just a loss of power. I'll post back what I find.

 

[workinonit]

RANDYT, I did the cylinder test and the port cylinder is the culprit. I'm not getting any spark so that pretty much makes it the ignition module or the cable from the module. Is there anything else that I'm missing?

 

[workinonit]

I'm accually surprised how well it runs on one cylinder. 9.5 HP is pretty weak.

 

[LittleBittyBigJohn]

I'm fighting the same issue on my big ZTR. It's a Gravely with a Kohler 27hp. Mine is hopefully a coil. The 1 cylinder thing is odd isn't it. Sounds fine until the 2nd one comes back in, then it's an ah ha moment!

 

[RandyT]

RANDYT, I did the cylinder test and the port cylinder is the culprit. I'm not getting any spark so that pretty much makes it the ignition module or the cable from the module. Is there anything else that I'm missing?

Need to disconnect the kill wire from the module to confirm that it is the module and not something to do with the kill wire circuit. If it comes down to the module I would go ahead and replace both because it always seems that after replacing just one the other one will fail within hours to just minutes. And sometimes a new module is not compatibility with each other.

 

[workinonit]

i just got back from the dealer with 2 of them. No sense in going in there and not replacing both.

sj, mine never came back in after it failed. I was waiting for the Ah Ha moment.